A difficulty arises in the use of protective barriers when a user desires to adjust the location of the barrier. For example only and not by way of limitation, structures with openings, such as buildings with windows, for example, very often include window shades. Normally the window shades are adjustable. They may be raised or lowered manually by means of draw strings and such. They may also be raised or lowered mechanically by use of motors operated by switches or remote controls. It is often difficult to manually raise and lower window shades to their full limits and it can be time consuming as well. Likewise, switch operated motor driven shades are subject to failure and are expensive to install and maintain.
By way of example, the prior art known to the Applicants includes devices that do not include cumbersome and dangerous pull cords, to their advantage, but are counterbalanced, manually operated devices only. U.S. Pat. Nos. 6,733,413 to Lagarde et al., 5,133,399 to Hiller et al. and 5,482,100 to Kubar exemplify the state of the art of these types of devices.
Other prior art devices include mechanical, motor operated devices that employ switches that can become damaged or deteriorate over time and are costly and time consuming to install such as the drapery actuator disclosed in U.S. Pat. Nos. 5,889,377 and 6,144,177 to Mao or the interconnected switches and sensors used to open and close a flexible curtain rollup door as in U.S. Pat. No. 6,082,433 to Vafaie et al. A serious drawback to these prior art motor operated systems is that, when the motor fails or the power goes out, the system is essentially locked in place. That is, the system must be disassembled and disconnected in order for a user to move the system without power.
Another U.S. Pat. No. 5,434,487 to Long et al., discloses a power operating system for a vehicle door for a van that includes a motor operable to power the door open or closed. When a manual movement of the van door a certain distance is detected while the motor is inactive, the motor is energized so as to move the door in the direction of the detected movement to complete the manually initiated door movement. As van doors are required to be either open or shut there is no provision for partial movement to a partially open or partially shut position. That is, Long et al. provides that any manual movement beyond a certain amount will activate a motor to power the door fully open or fully closed. Another U.S. Pat. No. 7,417,397 to Berman et al., discloses an automated shade system that uses software to monitor solar penetration and heat gain and such and to adjust shades as needed to control interior lighting and temperature.
Thus, while both manually operated and motorized devices are known, there is a need in the art for a simple, easy to install, easy to use and easy to maintain apparatus and method for a combination manual and motorized barrier adjustment device. It therefore is an object of this invention to provide a motorized barrier adjustment device that has no expensive switches and that can be operated manually and by motor to enable a user to exactly position a window barrier in any desired location along a window, for example only.